AI agents use draw_rectangle to create or update resources in Piskel MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Piskel MCP Server environment.
This tool modifies pixel art data within a project by adding graphical elements. It is reversible (the rectangle can be erased or overwritten), so it does not qualify as Destructive. It does not execute arbitrary code or trigger external operations, so it is not Execute. It does not move money or create financial obligations.
From the tool's definition Tool creates or modifies pixel art by drawing a rectangle shape within a project. Description states 'Draw a rectangle (outline or filled)', which creates new visual content.
Documented attack patterns abuse exactly the kind of access draw_rectangle gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Piskel MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for draw_rectangle:
{
"version": "1",
"default": "deny",
"tools": {
"draw_rectangle": {
"limits": [
{
"counter": "draw_rectangle_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}draw_rectangle stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
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Draw a rectangle (outline or filled). It is categorised as a Write tool in the Piskel MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Piskel MCP Server MCP server in PolicyLayer and add a rule for draw_rectangle: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Piskel MCP Server. Nothing to install.
draw_rectangle is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the draw_rectangle rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for draw_rectangle. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
draw_rectangle is provided by the Piskel MCP Server MCP server (yafeiaa/piskel-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Piskel MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
45 Piskel MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.